Teaching with basal fungal lineages
Powell, Martha .
Understanding Reproduction in Chytridiomycota.
Chytrids grow and survive in a wide range of habitats, in canopy debris, soil and water and from cold polar and alpine regions to the tropics. Their varied strategies for reproduction may be key to their success. These fungi are predominantly asexual, with dehiscence and discharge of unwalled zoospores from sporangial openings that range from inoperculate to operculate. The rate at which fully-formed zoospores become capable of motility varies, as does the time they swim. Ultimately zoospores locate a suitable substrate, withdraw their flagellum into their body, and produce a wall around the zoospore, developing into a thallus. Asexually produced thick-walled resting sporangia may form. Sexual reproduction is more commonly found among members of the most basal class within Chytridiomycota, the Class Monoblepharidomycetes, in which motile sperms fuse with non-motile oospores. Among the Class Chytridiomycetes, well-documented cases of sexual reproduction is more limited. Chytriomyces hyalinus produces resting sporangia zygotes as the result of rhizoidal fusion. Electron microscopy has demonstrated the migration of nuclei through the rhizoids of contributing thalli and fusion of nuclei in the zygote. In another chytrid, synaptonemal complexes in the zygotic nucleus at the time of resting spore germination indicate meiosis and reduction in ploidy. Classical studies of sexual reproduction, such as in Polyphagus euglenae demonstrate recombination through rhizoidal and thallus fusion and in Synchytrium sp. by gamete fusion.
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1 - University of Alabama, Department of Biological Sciences, Po Box 870344, Tuscaloosa, Alabama, 35487, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Cottonwood B/Snowbird Center
Date: Wednesday, July 29th, 2009
Time: 3:45 PM